Heat dissipation device

ABSTRACT

A heat dissipation device includes: a heat spreader having a first plate and a second plate, wherein the plates are connected to form a receiving space therebetween; a first capillary material provided on the first plate, the second plate, or both; at least one heat pipe having a cavity in communication with the receiving space, wherein the heat pipe is connected to the heat spreader at one end and is outside the heat spreader and closed at the other end; a second capillary material provided on the inner wall of the heat pipe; at least one fiber bundle of an elongated shape, wherein the fiber bundle has a portion in the receiving space and in contact with the first capillary material and another portion extending into the cavity and in contact with the second capillary material; and a working fluid in the receiving space and the cavity.

BACKGROUND OF THE INVENTION 1. Technical Field

The present invention relates to heat dissipation techniques and more particularly to a heat dissipation device incorporating a heat spreader and a heat pipe.

2. Description of Related Art

With the advancement of technology, and in order to satisfy user needs, many electronic products are designed in pursuit of ever better performance, and because of that, the heat generated by the electronic components inside those products is increasing. To effectively address the issue of high heat, heat spreaders and heat pipes are typically used, both of which feature good thermal conductivity. A heat dissipation device, for instance, may include a combination of a heat spreader and a heat pipe.

Taiwan Patent No. M286564 discloses a temperature-uniforming heat dissipator that includes a heat spreader, a plurality of heat pipes, and a fin assembly. The heat spreader has an upper plate, a lower plate, and a cavity formed between the plates. The heat pipes, each having an interior space, are fixed on the upper plate of the heat spreader and are mounted with the fin assembly. The temperature-uniforming heat dissipator is characterized mainly in that the interior spaces of the heat pipes are in communication with the cavity of the heat spreader.

As is well known in the art, a heat pipe or heat spreader has capillary structures for guiding the flow of a working fluid to achieve heat circulation, wherein the capillary structures are generally composed of sintered copper powder. In the temperature-uniforming heat dissipator of the afore-cited patent, the lower plate of the heat spreader provides a surface for contact with a heat source, and when the working fluid evaporates into a gaseous state and enters the heat pipes, the heat of the working fluid dissipates outward through the pipe walls and the fins. The temperature-uniforming heat dissipator, therefore, relies on a good working fluid to maintain efficient heat dissipation. Moreover, to ensure that the working fluid flows by capillary action, the heat spreader and the inner wall of each heat pipe of the temperature-uniforming heat dissipator must be provided with uninterrupted capillary structures, so an additional processing step is required to connect the capillary structures at the curved joints between the heat spreader and the heat pipes. This additional step, however, complicates the manufacturing process. Also, capillary structures composed of sintered copper powder cannot effectively transport a working fluid over a long distance.

To overcome the aforesaid drawbacks, the applicant believes that the foregoing temperature-uniforming heat dissipator needs improvement in heat conduction.

BRIEF SUMMARY OF THE INVENTION

In view of the drawbacks of the prior art, the primary objective of the present invention is to provide a heat dissipation device in which a heat spreader and a heat pipe are connected by a fiber bundle, and which is highly efficient in heat dissipation because the fiber bundle can transport a working fluid over a long distance with a high mass flux.

The heat dissipation device of the present invention includes a heat spreader, a first capillary material, at least one heat pipe, a second capillary material, at least one fiber bundle, and a working fluid. The heat spreader has a first plate and a second plate, and these two plates are connected to form a receiving space therebetween, wherein the receiving space is defined with a heated area. The first capillary material is provided on either or both of the first plate and the second plate and is located in the heated area. The heat pipe has a cavity in communication with the receiving space. One end of the heat pipe is connected to the heat spreader, and the other end of the heat pipe is located outside the heat spreader and is closed. The second capillary material is provided on the inner wall of the heat pipe. The fiber bundle has an elongated shape. A portion of the fiber bundle is in the receiving space while another portion of the fiber bundle extends into the cavity. The portion of the fiber bundle that is in the receiving space is provided on either or both of the first plate and the second plate and is in contact with the first capillary material. The portion of the fiber bundle that is in the cavity is in contact with the second capillary material on the inner wall of the heat pipe. The working fluid is in the receiving space and the cavity.

In the present invention, at least one fiber bundle, which is known to be capable of transporting a working fluid over a long distance with a high mass flux, is connected to both the first capillary material in the heated area and the second capillary material in the cavity to enhance heat dissipation efficiency, allowing the heat dissipation device of the present invention to overcome the drawbacks of the conventional improvements made to heat dissipators, particularly an increase in product size or cost and inconveniences in manufacture and use that result from the only conventional solution of increasing the number, or modifying the structure, of fins, heat pipes, or heat spreaders.

Preferably, the location where the heat pipe is provided does not correspond to that of the heated area.

The heat dissipation device of the present invention allows the joint between the heat spreader and the heat pipe to be changed in position according to user needs, thereby providing greater convenience in manufacture and use than the prior art.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The technical features of the present invention are detailed below with reference to some preferred embodiments in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of the first preferred embodiment of the present invention;

FIG. 2 is a bottom perspective view of the first preferred embodiment of the present invention, with the first plate removed;

FIG. 3 is a section view taken long line 3-3 in FIG. 1;

FIG. 4 is a bottom view of the first preferred embodiment of the present invention, with the first plate removed;

FIG. 5 is a bottom view of the second preferred embodiment of the present invention, with the first plate removed;

FIG. 6 is a sectional view taken along line 6-6 of FIG. 5;

FIG. 7 is a bottom perspective view of the third preferred embodiment of the present invention, with the first plate removed;

FIG. 8 is a bottom view of the third preferred embodiment of the present invention, with the first plate removed; and

FIG. 9 is a sectional view taken along line 9-9 in FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 to FIG. 4, the first preferred embodiment of the present invention provides a heat dissipation device 10 composed essentially of a heat spreader 11, a first capillary material 12, at least one heat pipe 13, a second capillary material 14, at least one fiber bundle 15, and a working fluid (not shown).

The heat spreader 11 has a first plate 111 and a second plate 112. The first plate 111 and the second plate 112 are connected in a sealing manner to form a receiving space 113 therebetween. The receiving space 113 is defined with a heated area H. The heat spreader 11 is further provided with an exhaust pipe 16. One end of the exhaust pipe 16 is located in the heat spreader 11 and is in communication with the receiving space 113. The other end of the exhaust pipe 16 is located outside the heat spreader 11 and is closed.

The first capillary material 12 is located in the heated area H. The first capillary material 12 may be provided on the first plate 111, the second plate 112, or both plates 111 and 112. In this embodiment, the first capillary material 12 is provided on the second plate 112 by way of example. Besides, the first capillary material 12 may be composed of sintered copper powder or a woven net. In this embodiment, for instance, the first capillary material 12 is composed of sintered copper powder.

There are three heat pipes 13 in this embodiment. Each heat pipe 13 has a cavity 131 in communication with the receiving space 113. Moreover, each heat pipe 13 has one end connected to the heat spreader 11 and the other end outside the heat spreader 11 and closed. The heat pipes 13 in this embodiment do not correspond in position to the heated area H, but it is totally alright that they do. In addition, the heat pipes 13 are inserted through a fin assembly 17.

The second capillary material 14 is provided on the inner wall of each heat pipe 13 and may be composed of sintered copper powder, a woven net, or a groove. In this embodiment, for example, the second capillary material 14 is composed of sintered copper powder.

There are three fiber bundles 15 in this embodiment. The fiber bundles 15 are elongated in shape, are partially located in the receiving space 113, and partially extend into the cavities 131 of the heat pipes 13. The portions of the fiber bundles 15 that are in the receiving space 113 may be provided on the first plate 111, the second plate 112, or both plates 111 and 112, and in this embodiment are provided on the second plate 112 for example. These portions of the fiber bundles 15 are in contact with first capillary material 12 in the heated area H. Meanwhile, the portions of the fiber bundles 15 that are in the cavities 131 are in contact with the second capillary material 14 in the heat pipes 13.

The working fluid is in the receiving space 113 and the cavity 131 of each heat pipe 13 and is uniformly contained in the first capillary material 12, the second capillary material 14, and the fiber bundles 15. The working fluid is well known in the art and difficult to show in the drawings and therefore will not be further described herein.

Having described the structure of the first preferred embodiment, the present specification continues to explain how the first preferred embodiment is used.

To use the heat dissipation device 10, referring to FIG. 1 through FIG. 4, the heated area H is brought into contact with a heat source (not shown) such that the temperature of the heated area H increases. Due to the rise of temperature, the working fluid contained in the first capillary material 12 evaporates into a gaseous state and permeates the receiving space 113. The gaseous working fluid then flows from the receiving space 113 to the cavity 131 of each heat pipe 13. In the meantime, the heat carried by the gaseous working fluid is conducted through the walls of the heat pipes 13 to the fin assembly 17 and dissipates outward. After that, the cooled gaseous working fluid condenses into a liquid state, is contained in the second capillary material 14, then flows back to the first capillary material 12 in the heated area H through the fiber bundles 15 by capillary action, and is contained in the first capillary material 12 again. The heat circulation mechanism described above enables the heat dissipation device 10 of the present invention to dissipate heat.

It can be known from the description of the first preferred embodiment that the fiber bundles 15 in the heat dissipation device 10 are connected to both the first capillary material 12 in the heated area H and the second capillary material 14 in the cavities 131. Hence, by virtue of the long-distance working fluid transportation ability of the fiber bundles 15 and the high mass flux of the working fluid through the fiber bundles 15, the heat dissipation device 10 has higher heat conduction efficiency than its prior art counterparts, in particular the aforementioned temperature-uniforming heat dissipator, whose capillary structures are formed by sintered copper powder.

The first preferred embodiment also shows that the heat dissipation device 10 of the present invention allows the heat pipes 13 to be connected to whichever part of the heat spreader 11 as needed, thus bringing about greater convenience in manufacture and use.

FIG. 5 and FIG. 6 show the heat dissipation device 20 provided by the second preferred embodiment of the present invention. The second preferred embodiment is generally the same as the first preferred embodiment except that the fiber bundles 25 abut against the first plate 211 and the second plate 212, and that the first capillary material 22 is provided on the first plate 211.

The heat dissipation device 20 disclosed in the second preferred embodiment is so configured that, with the fiber bundles 25 abutting against the first plate 211 as well as the second plate 212, a heat source (not shown) to be in contact with the heated area H2 can be brought into contact with either or both of the first plate 211 and the second plate 212 in the heated area H2. The only adjustment to be made is to have the first capillary material 22 in the heated area H2 correspond in position to the heat source. Since such an adjustment involves no other changes in structure or appearance, the aforesaid structural modification can be implemented with ease. The basic heat dissipation mechanism can be achieved even without the first capillary material 22, although the presence of the first capillary material 22 leads to higher heat dissipation efficiency. The functions of the other components are the same as those in the first preferred embodiment and therefore will not be described repeatedly.

FIG. 7 to FIG. 9 show the heat dissipation device 30 provided by the third preferred embodiment of the present invention. The third preferred embodiment is generally the same as the first preferred embodiment except that there are two heat pipes 33 and one fiber bundle 35; that the receiving space 313 further has a plurality of partitions 38 formed with a plurality of channels 39; that the partitions 38 are provided between and abut against the first plate 311 and the second plate 312 and separate the heated area H3 from the cavities 331; that the partitions 38 do not abut against the heated area H3, the channels 39, or the joints between the cavities 331 and the receiving space 313; that the heated area H3 and the cavities 331 of the heat pipes 33 are in communication with each other only through the channels 39; that the fiber bundle 35 is partially in contact with the first capillary material 32 and partially extends into the heat pipes 33 through any two channels 39; and that the two ends of the fiber bundle 35 are in contact with the second capillary material 34. The functions of the other components are the same as those in the first preferred embodiment and therefore will not be described repeatedly.

The heat dissipation device 30 disclosed in third preferred embodiment is so configured that the partitions 38 abutting against the first plate 311 and the second plate 312 provide the heat dissipation device 30 with additional structural support. Moreover, with the fiber bundle 35 extending through only some of the channels 39, the working fluid is guided through the channels 39 where the fiber bundle 35 extends when in a liquid state, and flows through the channels 39 where the fiber bundle 35 is absent when in a gaseous state. Thus, the partitions 38 formed with the channels 39 not only reinforce the heat dissipation device 30 structurally, but also are effective in guiding the liquid-state portion and the gaseous portion of the working fluid through different channels 39, preventing the high-speed gaseous portion from interfering with the reflow of the working fluid; consequently, high thermal conduction efficiency can be achieved. 

What is claimed is:
 1. A heat dissipation device, comprising: a heat spreader having a first plate and a second plate, wherein the first plate and the second plate are connected to form a receiving space therebetween, and the receiving space is defined with a heated area; a first capillary material provided on either or both of the first plate and the second plate and located in the heated area; at least one heat pipe having a cavity in communication with the receiving space, wherein the heat pipe has an end connected to the heat spreader and an opposite end located outside the heat spreader and closed; a second capillary material provided on an inner wall of the heat pipe; at least one fiber bundle of an elongated shape, wherein the fiber bundle has a portion located in the receiving space and another portion extending into the cavity, the portion of the fiber bundle that is located in the receiving space is provided on either or both of the first plate and the second plate and is in contact with the first capillary material, and the portion of the fiber bundle that extends into the cavity is in contact with the second capillary material on the inner wall of the heat pipe; and a working fluid in the receiving space and the cavity.
 2. The heat dissipation device of claim 1, wherein the heat pipe extends through a fin assembly.
 3. The heat dissipation device of claim 1, wherein the first capillary material is composed of sintered copper powder or a woven net.
 4. The heat dissipation device of claim 1, wherein the second capillary material is composed of sintered copper powder, a woven net, or a groove.
 5. The heat dissipation device of claim 1, wherein the receiving space further has a partition formed with a plurality of channels, the partition abuts against a portion of the first plate and a portion of the second plate and separates the heated area from the cavity, the heated area and the cavity are in communication with each other through the channels, and the fiber bundle is provided in some of the channels.
 6. The heat dissipation device of claims 1, wherein the heat pipe does not correspond in position to the heated area.
 7. The heat dissipation device of claim 5, wherein the heat pipe does not correspond in position to the heated area. 